I'm working on making an SCP-themed GURPS worldbook. I've made quite a bit of progress so far, but there's still a ways to go.
What I have so far:
A map of site 19 (made using a random dungeon map generator) with details for each room.
a powerpoint file containing various SCP documents.
campaign notes
a powerpoint of the site-19 map and campaign notes that has way too much effort put into it
some NPC tables.

What I'm currently working on:
filling out the documents powerpoint and creating document images that the GM can print out and share.

What is still needed:
some of the SCPs don't have images
a list of advantages and disadvantages unique to the SCP mythos and their point costs
a "monsters" list for animate SCPs, detailing their stats (i've worked on the stats for many of them, but I'm not sure about formatting and the like.)
an anomalous item's list for inanimate SCPs.
development of other site locations (I've started on a document for site 17, but it still needs to be fleshed out)
miscellaneous world-building

and the best part is: the whole thing is public on google drive, so anyone can contribute to it or use it for their own tabletop campaigns.
If you'd like to help, click on the Google Drive link. You can add any of the things on the list of things to add, or make revisions to the things already there (within reason). If you'd like to make your own map for Site-19, feel free to do so.

GURPS Illuminati: The whole idea is a secret organization that works in the background of a "constantly" (if the GM wants to) shifting reality. Magic is concealed, along with aliens, and they pull the strings of the public. The Foundation isn't this, but it would help to look through it to get some conspiracy ideas for GURPS SCP Foundation.

GURPS Warehouse 23: A warehouse that stores all the artifacts and unnatural tech and chems in one location, guarded by people working there. Or discovered abandoned and the characters go looking through the containers (however you wish to put it). The Foundation is well known for storing the impossible. Using the Warehouse 23 Worldbook may help in establishing how certain things can be kept within the Sites and Research Locations

GURPS Technomagic: A incident in 1947, created the world in which magic now exists within our world once again. Mutants and creatures of myth and lore become as real as we do, and with today's tech, we can do magic though it. The Foundation has tech and abilities that could be construed as Technomagic. Maybe there's something there that works similar to the Foundation's methods of capture.

GURPS Black Ops: Top Secret Missions that require people similar to Field Ops type people within the Foundation.

GURPS The Prisoner: Based on the 1967 British tv series of the same name, the whole idea of the Village seems to work on SCP based logic. I don't know if you've seen the series, but it's a good idea to get yourself familiar to the series to understand GURPS The Prisoner.

All I remember (when I had an idea like you to make a GURPS SCP Foundation) was that I would use the combinations of all 5 books to make the Foundation Universe, and the method of setting up new character advantages and disavantages. I didn't think of including Skips or their adv. and disadv.
Another thing, the SCP Foundation would need to be flexible enough to fit into other Setting Worldbooks (i.e. Atomic Horror, Cliffhanger, Steampunk, etc. etc.), yet still work on its own for the RPG.

Basically, we'll need to figure out how to fit the Foundation into a GURPS Framework.
I also found my previous post: GURPS SCP Foundation
Just to look at my notes.